Thread: Window Flicker

I was trying to make my own tab control so I can open several files in my program. I was trying to do this by creating a richedit control for each tab and then hiding and showing those when a user clicks on a different tab. Maybe it isn't the best way, but it seems to work ok, except the edit controls flicker when switching back and forth.

If I handle the WM_ERASEBKGND message and just return 0, there is no flicker. Problem is, I need to erase the background except where the edit control is. So what is the easiest way to erase the entire background except for a certain rect?

According to this page, I should be able to call InvalidateRect with the last parameter as false, but that doesn't seem to work:

Code:

case WM_PAINT:
{
      RECT rc;
      GetWindowRect(hRiched[currentEdit],&rc);
      InvalidateRect(hwnd,&rc,0);
      tab.RedrawTabs();      
      
}

Calling UpdateWindow doesn't seem to have any effect...

UpdateWindow() just bypasses the OS msg que and posts directly to your apps callback.

InvalidateRect() sends a WM_PAINT msg.

So not a good idea to call either from within WM_PAINT.

Call both only when the TAB changes.

Hm well with a bit of messing around I came up with this code to handle the WM_ERASEBKGND message:

Code:

      RECT rc;
      HDC hdc = GetDC(hwnd);
      GetWindowRect(hRiched[currentEdit],&rc);
      ExcludeClipRect(hdc,rc.left,rc.top-1-GetSystemMetrics(SM_CYMENUSIZE)-GetSystemMetrics(SM_CYCAPTION),rc.right,rc.bottom-GetSystemMetrics(SM_CYMENUSIZE)-GetSystemMetrics(SM_CYCAPTION));
      GetClientRect(hwnd,&rc);
      HBRUSH hbr = CreateSolidBrush(RGB(88,87,104));
      FillRect(hdc,&rc,hbr);
      DeleteBrush(hbr);
      ReleaseDC(hwnd,hdc);
      return 0;

Although I'm not sure how to be sure the rect that I get for the rich edit window lines up properly...

Which kind of ties in to a weird problem. When I create my main window I create it with the following styles:

Code:

WS_POPUP|WS_CAPTION|WS_MAXIMIZE|WS_SYSMENU|WS_MINIMIZEBOX|WS_CLIPCHILDREN

And it looks the way I want when I run it from VS, but when I don't run it from VS, it isn't maximized (still takes up the whole screen,but has a border). So you can move it around, which I don't want.

I was trying to make my own tab control so I can open several files in my program. I was trying to do this by creating a richedit control for each tab and then hiding and showing those when a user clicks on a different tab. Maybe it isn't the best way, but it seems to work ok, except the edit controls flicker when switching back and forth.

You're probably are getting flicker because when you hide the rich text window you draw what's behind the rich text window(the erase background event) and when you show the other rich text you replace the background. What you want to do is hide one rich text window, but not invalide the control's rectangle, and then replace with the other rich text window. It might be better to somehow change the each rich text window's zorder so that one window appears above the other. I don't know enough of the win32 API to help you with the specifics.